U.S. patent application number 12/778669 was filed with the patent office on 2011-11-17 for suspended operator platform.
This patent application is currently assigned to Metalcraft of Mayville, Inc.. Invention is credited to James W. Hall, David J. Sugden.
Application Number | 20110277433 12/778669 |
Document ID | / |
Family ID | 44910492 |
Filed Date | 2011-11-17 |
United States Patent
Application |
20110277433 |
Kind Code |
A1 |
Sugden; David J. ; et
al. |
November 17, 2011 |
SUSPENDED OPERATOR PLATFORM
Abstract
A suspended operator platform for use with a ride-on lawnmower
or the like is connected to a rigid chassis of the ride-on
lawnmower by a suspension system that has a parallelogram linkage.
The operator platform supports an entire body of the operator and
isolation mounts connect a seat assembly to the operator platform.
Steering controls of the ride-on lawnmower are connected to the
operator platform so that the steering controls move with the
operator platform and are suspended and/or isolated from the
chassis. The suspension system includes a course-stiffness adjuster
and a fine-stiffness adjuster that for adjusting suspension
stiffness to correspond to a particular operator and/or
terrain.
Inventors: |
Sugden; David J.; (Horicon,
WI) ; Hall; James W.; (Princeton, WI) |
Assignee: |
Metalcraft of Mayville,
Inc.
|
Family ID: |
44910492 |
Appl. No.: |
12/778669 |
Filed: |
May 12, 2010 |
Current U.S.
Class: |
56/10.1 ;
296/65.02 |
Current CPC
Class: |
B60N 2/544 20130101;
A01D 34/66 20130101; A01D 67/04 20130101; B60N 2/507 20130101 |
Class at
Publication: |
56/10.1 ;
296/65.02 |
International
Class: |
A01D 34/00 20060101
A01D034/00; B60N 2/005 20060101 B60N002/005 |
Claims
1. A riding utility vehicle, comprising: a chassis that supports a
drive train; a seat; an operator platform that supports the seat
and an entire body of an operator during use of the utility
vehicle; a suspension system connecting the operator platform to
the chassis and permitting relative movement therebetween; and
steering controls for directing movement of the utility vehicle,
the steering controls being connected to and moving in unison with
the operator platform.
2. The riding utility vehicle of claim 1, the suspension system
further comprising a stiffness adjuster that adjusts the stiffness
of the suspension system, the stiffness adjuster being operable by
a seated operator.
3. The riding utility vehicle of claim 1, the suspension system
further comprising a spring that biases the operator platform
toward a default position and (i) a course-stiffness adjuster that
is configured to adjust a preload setting of the spring, and (ii) a
fine-stiffness adjuster that is configured to adjust an angle
defined between the spring and the operator platform.
4. The riding utility vehicle of claim 3, the course-stiffness
adjuster further comprising (i) a seat that supports the spring and
that is moveable along a longitudinal axis of the spring, and (iii)
a cam that at least indirectly engages the seat, and wherein the
cam is vertically movable relative to the operator platform to
correspondingly move the seat to advance or regress with respect to
the longitudinal axis of the spring so as to vary a preload on the
spring.
5. The riding utility vehicle of claim 3, the fine-stiffness
adjuster further comprising (i) a spring linkage that is connected
to the spring, and (ii) a movable lever that is connected to the
spring linkage, and wherein movement of the lever is translated
through the spring linkage so as to vary an inclination of the
spring with respect to at least one of the chassis and the operator
platform.
6. The riding utility vehicle of claim 3, further comprising a seat
and at least one elastomeric isolation mount connecting the seat to
the operator platform to reduce transmission of vibrations
therebetween.
7. The riding utility vehicle of claim 3, further comprising a seat
and at least one isolation mount connecting the seat to the
operator platform and reducing transmission of vibrations
therebetween, the isolation mount including a top portion and a
bottom portion, the isolation mount being (i) transversely flexible
so as to move the top and bottom portions transversely with respect
to each other, and (ii) longitudinally compressible so as to move
the top and bottom portions closer to each other, and wherein less
force is required to transversely flex the isolation mount than is
required to longitudinally compress the isolation mount a common
distance.
8. The riding utility vehicle of claim 1, the suspension system
further comprising a bump-stop attached to the chassis and limiting
downward travel of the operator platform with respect to the
chassis.
9. The riding utility vehicle of claim 1, wherein the steering
controls comprise a steering lever and a cylinder that is connected
to the steering lever and that resists steering lever movement.
10. The riding utility vehicle of claim 1, the suspension system
further comprising a front linkage that extends angularly between
the chassis and a front portion of the operator platform and a back
linkage that extends angularly between the chassis and a back
portion of the operator platform, wherein the front and back
linkages restrict movement of the operator platform to at least one
of (i) vertical, and (ii) fore and aft movements respect to the
chassis.
11. The riding utility vehicle of claim 1, wherein the vehicle is a
lawnmower.
12. A riding utility vehicle, comprising: a chassis that supports a
drive train; a seat; an operator platform that supports the seat
and an entire body of an operator during use of the utility
vehicle; a suspension system connecting the operator platform to
the chassis, the suspension system including (i) a front linkage
that extends angularly between the chassis and a front portion of
the operator platform, and (ii) a back linkage that extends
angularly between the chassis and a back portion of the operator
platform.
13. The riding utility vehicle of claim 12, further comprising
steering controls for directing movement of the utility vehicle,
the steering controls being connected to and moving in unison with
the operator platform.
14. The riding utility vehicle of claim 12, further comprising a
stiffness adjuster that controls suspension flexing stiffness as
the operator platform moves with respect to the chassis.
15. A utility vehicle, comprising: a chassis that supports a drive
train; a seat; an operator platform that supports the seat and an
entire body of an operator during use of the utility vehicle; and a
linkage system connecting the operator platform to the chassis, the
linkage system allowing vertical movement of the operator platform
with respect to the chassis and substantially preventing (i)
transverse swaying of the operator platform with respect to the
chassis, (ii) rolling of the operator platform about a longitudinal
axis of the platform, and (iii) yawing of the operator platform
about an upright axis extending longitudinally through the
chassis.
16. The utility vehicle of claim 15, the linkage system further
comprising a back linkage connected to a back portion of the
operator platform and a front linkage connected to a front portion
of the operator platform.
17. The utility vehicle of claim 16, wherein the front and rear
linkages form, in combination with one another, the operator
platform, and the chassis, a parallelogram linkage assembly.
18. The utility vehicle of claim 15, further comprising a spring
that supports the operator platform.
19. The utility vehicle of claim 18, wherein an angle defined
between the spring and a rear linkage of the linkage system is
adjustable by a seated operator of the utility vehicle.
20. The utility vehicle of claim 19, further comprising a spring
linkage that is connected to the spring and movable lever that is
connected to the spring linkage, wherein movement of the lever is
translated through the spring linkage so as to adjust the angle
defined between the spring and the rear linkage.
21. A riding utility vehicle, comprising: a chassis that supports a
drive train; a seat; an operator platform that supports the seat
and an entire body of an operator during use of the utility
vehicle; a suspension system connecting the operator platform to
the chassis and permitting relative movement therebetween; steering
controls for directing movement of the utility vehicle, the
steering controls being connected to and moving in unison with the
operator platform; a stiffness adjuster that adjusts the stiffness
of the suspension system, the stiffness adjuster being operable by
a seated operator.
22. A riding utility vehicle, comprising: a chassis that supports a
drive train and a mower deck; a seat; an operator platform that
supports the seat and an entire body of an operator during use of
the utility vehicle; a suspension system connecting the operator
platform to the chassis and including (i) a course-stiffness
adjuster that is configured to adjust a suspension stiffness
setting within a first range of stiffness settings, and (ii) a
fine-stiffness adjuster that, with respect to each of the first
range of settings, is configured to adjust the suspension stiffness
setting within a second range of stiffness settings.
23. The riding utility vehicle of claim 22, the suspension system
further comprising at least one linkage that permits vertical
travel of the operator platform with respect to the chassis and
that transversely captures the operator platform with respect to
the chassis so as to substantially prevent (i) transverse swaying
of the operator platform with respect to the chassis, (ii) rolling
of the operator platform about a longitudinal axis of the platform,
and (iii) yawing of the operator platform about an upright axis
extending through the chassis.
24. The riding utility vehicle of claim 22, the course-stiffness
adjuster further comprising a spring having a variable preload
setting, and wherein varying the preload setting of the spring so
that the spring is relatively more compressed in a default state
provides a relatively stiffer flexing of the suspension, and
varying the preload setting of the spring so that the spring is
relatively less compressed in the default state providing a softer
flexing of the suspension.
25. The riding utility vehicle of claim 22, the fine-stiffness
adjuster further comprising a spring that has a variable angle
between the spring and the operator platform, and wherein changing
the variable angle between the spring and the operator platform
adjusts the suspension between a relatively stiffer flexing of the
suspension and a relatively softer flexing of the suspension.
26. The riding utility vehicle of claim 25, the fine-stiffness
adjuster further comprising a handle that is connected to the
spring, such that movement of the handle correspondingly changes
the variable angle between the spring and the operator
platform.
27. A ride-on mower, comprising: a chassis that supports a drive
train and a mower deck; an operator platform that supports an
entire body of an operator during use of the ride-on mower; left
and right steering control levers that are mounted on and move with
the operator platform; a seat that is supported on the operator
platform; elastomeric isolation mounts disposed between the seat
and the operator platform; and a suspension system connecting the
operator platform to the chassis and permitting relative movement
therebetween, the suspension system including; a spring/shock
system that maintains the operator platform in a fully raised
position when no operator is on the operator platform; a stiffness
adjuster connected to the spring/shock system and controlling the
stiffness of the suspension as the operator platform moves with
respect to the chassis, the stiffness adjuster being operable by a
seated operator to adjust the stiffness of the suspension; a front
linkage that extends angularly between the chassis and a front
portion of the operator platform; and a back linkage that extends
angularly between the chassis and a back portion of the operator
platform.
28. A method of operating a utility vehicle having a suspension
system that connects an operator platform to a chassis while
permitting relative movement with respect thereto, the operator
platform supporting a seat, the method comprising: establishing a
first setting of a suspension flexing stiffness; operating the
ride-on mower; and while an operator is upon the ride-on mower,
adjusting the suspension performance characteristic to a second
setting that provides either (i) a relatively softer flexing of the
suspension, or (ii) a relatively stiffer flexing of the suspension,
with respect to the first setting.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to off-road light duty vehicles such
as lawnmowers and, more particularly, to a suspension system for a
ride-on mower.
[0003] 2. Discussion of the Related Art
[0004] Rider versions of self-propelled mowers or "ride-on mowers"
are known in the lawn grooming or lawn care industries. Operators
of ride-on mowers can mow for relatively long periods of time,
since the operators are seated during use. Despite being seated
while mowing, operating ride-on mowers can be physically demanding
because the operators can be exposed to shocks, vibrations, or
other loads, that are generated by the ride-on mower during use or
that result from driving the ride-on mower across uneven terrain.
Such vibrations, or shock-type or other loads, can transmit through
the ride-on mower chassis, foot rest, seat, and controls, and into
the legs, bodies, and arms of the operators. For the sake of
convenience, these loads that are transmitted to the operator by or
through the mower are simply referred to as "shock loads" herein
for the sake of brevity.
[0005] Various attempts have been made to reduce the imposition of
shock loads to operators by using suspension seats that are
suspended by springs and/or dampers to isolate the seats from the
chassis. However, such seat suspensions fail to reduce transmission
of vibrations, or shock-type or other loads, through non-seat
components. Accordingly, seat suspensions leave operators
susceptible to exposure of shock loads through foot rests,
controls, or components other than the seat that are in contact
with the operator.
[0006] U.S. Patent Application Publication No. 2006/0290080 (the
'080 application) discloses a ride-on mower that partially
alleviates these problems by providing a platform that is isolated
from a chassis by springs at each corner of the platform. The
operator's seat is mounted on the platform, and the front portion
of the platform serve as an operator footrest. While this system
reduces the imposition of shock loads to the operator's feet, the
corner mounted springs allow the platform to roll about a
longitudinal axis, yaw, and transversely sway, to an extent
permitted by a pair of hinges at the front of the platform and a
stabilizer bar at the back of the platform. Despite being limited
to some extent by the front hinges and back stabilizer bar, such
partially limited movements may lead to oscillations of the
platform relative to the chassis during certain operating
conditions or may be perceived by an operator as being an
undesirably loose connection between the platform and chassis. In
addition, the steering levers are mounted directly to the chassis,
whereby relative movements between the platform and chassis result
in relative movements between an operator and the steering levers.
Such relative movements between the operator and steering levers
can give the steering levers a meandering feel during use, which
may not be desirable. Furthermore, mounting the steering levers
directly to the chassis allows vibrations, or shock-type or other
loads, which are transmitted through the chassis, to also be
transmitted through the steering levers and into the arms of the
operator.
[0007] Yet other attempts have been made to reduce the imposition
of shock loads to an operator by using chassis suspension systems
that support the entire chassis, from wheels in a manner that is
somewhat analogous to an automobile suspension. These systems
usually take the form of a system of springs supporting the chassis
on the wheels. Such chassis suspension systems are complex,
expensive, and require substantial maintenance. They also must be
sufficiently robust to support the entire chassis and everything
supporting on it, including the seat, the operator, the mower deck,
the drive train, etc. They also allow the mower deck to move with
respect to underlying ground surfaces. This relative movement can
lead to reduced cutting performance. For example, during rapid
deceleration occurring during a braking event, the mower deck may
"nose dive" or pitch downwardly further into the grass, resulting
in "scalping" or an undesirably short cut during the nose-diving
occurrence.
[0008] Typical suspension systems also provide non-adjustable
stiffness deemed to be ideal for a "typical" operator weight. Of
course, operators' weights vary dramatically, and even operators'
of a given weight may have differences of opinion as to what is
considered to be an ideal stiffness under prevailing operating
conditions, which may themselves vary. For example, a given
operator may prefer a stiffer suspension on smooth terrain than on
a rougher or uneven terrain. Traditional suspension systems cannot
accommodate these changing needs.
[0009] Prior art lawnmowers and other vehicles having suspension
systems also tend to have relatively high centers of gravity,
reducing the stability of the vehicles.
[0010] Many of the problems discussed above are also experienced by
other light utility vehicles, such as all terrain vehicles having
dumping load carrying beds. One such vehicle is manufactured by
John Deere & Co. under the trade name Gator.
SUMMARY OF THE INVENTION
[0011] In light of the foregoing, a suspended operator platform of
a lawnmower or other riding light utility vehicle is desired that
improves the state of the art by overcoming one or more of the
aforesaid problems of the prior art.
[0012] It is also desired to provide a suspended operator platform
that suspends or isolates at least some controls from the rigid
chassis of the ride-on mower. For instance, steering controls may
be mounted on the suspended platform so as to move in unison with
the suspended operator platform.
[0013] It is also desired to provide a suspension system that has a
stiffness adjuster that is configured to accommodate for body
weight differences of different users and/or to accommodate varying
user preferences.
[0014] In accordance with an aspect of the invention, at least some
of these desires are fulfilled by providing a suspended operator
platform for use with a ride-on mower or other light utility
vehicle. The suspended operator platform is connected to a rigid
chassis of the ride-on mower by a suspension system that has a
parallelogram linkage. The operator platform supports an entire
body of the operator. Steering controls of the vehicle are
connected to the operator platform so as to move with the remainder
of the platform.
[0015] In accordance with another aspect of the invention, a
vehicle suspension system for a light utility vehicle may include
an operator stiffness adjuster that permits a seated operator to
adjust the stiffness of the suspensions system. That stiffness
adjuster may comprise a "fine" stiffness adjuster that can be
utilized in conjunction with a separate, "course-stiffness
adjuster," to provide for wider range of adjustment.
[0016] In accordance with another aspect of the invention, a
vehicle suspension system for a light utility vehicle may include a
system of linkages that permits the operator platform to swing fore
and aft as a unit while preventing any side to side movement and/or
any pitching or yawing movement.
[0017] In accordance with yet another aspect of the invention, an
operator's seat is vibrationally isolated from a suspended operator
platform by a system of elastomeric isolation mounts.
[0018] In accordance with another aspect of the invention, a coil
over shock is aligned longitudinally and/or transversely with a
center of gravity of a sprung weight of the mower.
[0019] Various other features, embodiments and alternatives of the
present invention will be made apparent from the following detailed
description taken together with the drawings. It should be
understood, however, that the detailed description and specific
examples, while indicating preferred embodiments of the invention,
are given by way of illustration and not limitation. Many changes
and modifications could be made within the scope of the present
invention without departing from the spirit thereof, and the
invention includes all such modifications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Preferred exemplary embodiments of the invention are
illustrated in the accompanying drawings, in which like reference
numerals represent like parts throughout, and in which:
[0021] FIG. 1 is an isometric view of a ride-on mower incorporating
a suspended operator platform in accordance with the present
invention;
[0022] FIG. 2 is a partially exploded isometric view of the ride-on
mower shown in FIG. 1;
[0023] FIG. 3 is a left-side sectional view of the operator
platform, portions of the chassis, and other portions of the mower
shown in FIG. 1;
[0024] FIG. 4 is a cross sectional view, taken generally along line
4-4 in FIG. 1;
[0025] FIG. 5 is a left-side sectional view of the operator
platform and other mower components shown in FIG. 3, with the
operator platform of the suspension system fully compressed;
[0026] FIG. 6 is a left-side sectional view of the operator
platform and other mower components shown in FIG. 3, with the
operator platform of the suspension system fully extended;
[0027] FIG. 7 is a left-side elevation view of portions of the
steering controls of the ride-on mower shown in FIG. 1;
[0028] FIG. 8 is an isometric view of portions of the
fine-stiffness adjuster extending through a wall of the operator
platform shown in FIG. 2;
[0029] FIG. 9 is a close-up isometric view of the fine-stiffness
adjuster shown in FIG. 2;
[0030] FIG. 10 is a close up, left-side sectional elevation view of
a portion of the suspension system of the ride on-mower shown in
FIG. 1; and
[0031] FIG. 11 is a variant of the close up, left-side sectional
elevation view of the portion of the suspension system shown in
FIG. 10.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] The drawings illustrate a preferred exemplary embodiment of
the invention as incorporated into a self-propelled, ride-on mower
5. It should be understood, however, that the invention is usable
with other mowers and other light utility type vehicles as well.
With respect to the embodiment of a ride-on mower illustrated in
the accompanying drawings, it will be appreciated that like
reference numerals represent like parts throughout the
drawings.
[0033] Referring initially to FIGS. 1 and 2, a self-propelled,
ride-on mower 5 is configured as a zero-turn lawnmower and includes
a chassis 10, an operator platform 70, and a suspension system 100
that suspends the operator platform 70 from the chassis in a manner
that isolates an operator from vibrations, or shock-type or other
loads that are generated on or by the mower 5 during use or result
from driving the mower 5 across uneven terrain, explained in
greater detail elsewhere herein. As mentioned above, those loads
are individually and collectively referred to herein as "shock
loads" for the sake of conciseness. A drive train is supported in a
generally rigid manner in chassis 10 that includes a frame 12 with
a frame middle rail 13 (FIG. 2) and outer frame rails 15 extending
in a generally horizontal direction, the frame rails having
bumpstops 17 (FIG. 2) that limit downward travel of the operator
platform 70 relative to the chassis 10. Mower deck 20 is supported
by frame 12, typically by being suspended from the frame by a
system of chains and/or linkages. Mower deck 20 can be a
multi-blade cutting deck, including multiple rotating cutting
blades that are positioned and driven in a conventional manner. It
is noted that deck 20 could alternatively be a single blade cutting
deck. It is also appreciated that deck 20 is movably attached to
frame 12, thereby allowing a user to specify a distance of deck 20
from a cutting surface to provide a number of desired cutting
heights. A deck adjustment lever, which is part of a deck height
and leveling assembly, allows an operator to raise and lower deck
20 as desired. A suitable deck height and leveling assembly is seen
in U.S. application Ser. No. 11/945,734, filed Nov. 27, 2007, and
entitled "Lawnmower Cutter Deck with Independently Operable Deck
Leveler Assemblies" which is incorporated herein by reference in
its entirety. Deck 20 is provided between a pair of independently
driven drive wheels 30 and 32 and a pair of casters 34, 36, at the
rearward and forward portions of the chassis 10, respectively.
[0034] Still referring to FIGS. 1 and 2, drive wheels 30, 32 are
operatively connected to an engine 40, while casters 34, 36 are
undriven and are pivotally attached to a front portion of frame 12.
Engine 40 sits on the frame 12, toward the back of the ride-on
mower 5. A control system 45 is provided on opposing sides of seat
assembly 60 in which the operator sits during use. The operator
manipulates control system 45 to operate the mower.
[0035] Referring to FIGS. 2 and 7, a pair of hydraulic drives 52,
54 are mounted on the chassis 10 and drive the drive wheels 30, 32,
with each hydraulic drive 52, 54 being associated with and driving
a dedicate one of the drive wheels 30, 32. Each hydraulic drive 52,
54 preferably includes a pump and a motor that are combined to form
a single unit, each unitary or combined pump and motor of the
hydraulic drives 52, 54 being mounted sufficiently low on the
chassis 10 so as to contribute to a relatively low center of
gravity of the mower 5. Combining the pumps and motors also further
reduces the number of moving parts. Preferably, each pump of the
hydraulic drives 52, 54 is an axial-piston type pump which includes
an internal tilting swash plate (not shown) which can be rotated to
vary the pump discharge rate from a zero flow, also referred to as
neutral, up to a maximum flow in either the forward or reverse
directions. A pair of calibration bodies, or other suitable tuning
controls, cooperates with the pumps allowing an operator to
calibrate the output of each respective pump so that mower 5 moves
in a straight line when no turning function is being performed.
Preferably, the pumps have fan blades that are mounted to ends of
pump shafts and which produce heat dissipating air flows around the
hydraulic drives 52, 54. The motor of each hydraulic drive 52 or 54
is a piston motor that is mechanically and fluidly connected to the
associated pump and that transmits torque to an integrated axle of
the drive 52 or 54 via an internal gear train.
[0036] Still referring to FIGS. 2 and 7, control system 45 includes
steering controls 55 that cooperate with the hydraulic drives 52,
54 for rotating the drive wheels 30, 32. Steering controls 55
include a pair of levers 58A, 58B that are pivotally attached to
the operator platform 70, as seen best in FIG. 7. Still referring
to FIG. 7 and shown with respect to components on the left side of
the mower 5, lever 58A is connected by a push/pull cable 59 to a
swash plate actuator on the left hydraulic drive 52. A second
push/pull cable (not shown) connects lever 58B and a swash plate on
the right hydraulic drive 54 on the right side of the mower 5,
although not show. Moving the levers 58A, 58B pushes and/or pulls
the cables which correspondingly move the swash plate actuators so
as to result in forward, rearward, and/or turning motion of the
mower 5 depending on the direction and magnitude of movement of the
levers 58A, 58B. Cylinders (only one of which is shown at 58C) are
connected to the levers 58A, 58B and the operator platform 70 to
resist steering lever movement in order to impart "feel" to a
steering operation.
[0037] Still referring to FIGS. 2 and 7, pivoting the levers 58A,
58B in a common direction forward or backward from a neutral
position result in forward or reverse propulsion of the mower 5 at
a speed proportional to the magnitude of pivoting, allowing
two-lever controlled equipment manipulation techniques are used for
maneuvering the mower. For instance, turning to the left or right
while propelling the mower 5 can be achieved by "stroking" or
pivoting the levers 58A, 58B different distances about lateral
pivot axes 57A, 57B (only one of which is shown at 57A in FIG. 7)
from the neutral position, but in a common direction, and
zero-radius turns are achieved by pivoting the levers 58A, 58B a
common distance from the neutral position, but in opposite
directions.
[0038] Referring now to FIG. 2, the seat assembly 60 is positioned
with respect to the control system 45 so that the operator has
comfortable access to the levers 58A, 58B and other components of
the control system 45. Operator comfort is further enhanced by
suspending the operator platform 70, the seat assembly 60, and the
levers 58A and 58B from the rigid chassis 10 by the suspension
system 100. The seat assembly 60 is mounted on the platform 70 by
isolation mounts 65 that further reduce the imposition of shock
loads to the operator and that permit limited movement of the seat
relative the operator platform 70.
[0039] Referring to FIGS. 2 and 3, seat assembly 60 includes a pan
62 to which a track 63 is mounted, the track 63 allowing forward
and backward position adjustment of the seat assembly 60 relative
to the platform 70. Four isolation mounts 65 mount corners of the
pan 62 on a seat support tier 72 of the operator platform 70. The
isolation mounts 65 reduce the imposition of vibrations to the
operator and also provide a secondary suspension for the operator,
supplementing the suspension system 100. They also permit limited
movement of the seat assembly 60 relative to the platform,
improving the "ride" or "feel" by, for example, reducing the amount
of vibrations and/or other dynamic forces that can be transferred
through the seat and felt by the operator. The isolation mounts 65
are made from an elastomeric material and provide compliance in all
directions, with greater compliance preferably being provided
horizontally than vertically, whereby less force is required to
flex the isolation mounts 65 in a transverse direction than is
required to longitudinally compress the isolation mounts 65. Each
isolation mount 65 of this embodiment is a so-called "five to one"
mount that is 5 times more compliant horizontally than vertically.
Each isolation mount 65 includes a relatively narrower top portion
66 (FIG. 4) and a relatively wider bottom portion 67 (FIG. 4) that
are defined along a conically tapering sidewall.
[0040] Referring still to FIGS. 2 and 3, a wall 74 extends
angularly down from a front portion of the seat support tier 72 of
the operator platform 70 and connects the seat support tier 72 to a
planar horizontal pan or foot support tier 76 that defines a front
portion of the operator platform 70. The front end of the foot
support tier 76 forms an upwardly angled shelf 78.
[0041] Referring again to FIGS. 1 and 2, suspension system 100 is
configured to support an entire body of the operator, the operator
platform 70, and the components attached to the operator platform
70 such as steering controls 55. A combined weight of all of these
defines a sprung weight that is supported by the suspension system
100. Substantially the rest of the mower 5 is considered "rigid" or
defines an unsprung weight of the mower 5, whereby the chassis 10,
the mower deck 20, and the engine 40, are not supported by the
suspension system 100. Such components of the mower 5 that are not
supported by the suspension system 100 are generally represented by
the subassembly of major mower 5 components seen on the right side
of FIG. 2. This configuration of suspension system 100 enhances
operator comfort by isolating the entire operator, including the
operator's hands and feet, from shock loads. Isolating the mower
deck 20 from the suspension system 100 prevents scalping that could
otherwise occur if the mower deck 20 were to move with the
suspension system 100 during a breaking operation. Isolating the
mower deck 20, chassis 10, engine 40, hydraulic drives 52, 54, etc.
from the suspension system 100 dramatically reduces the mass that
otherwise would be supported by the suspension system 100,
increasing the responsiveness of the suspension system.
[0042] Referring now to FIGS. 2, 3, 5, and 6, the suspension system
100 of this embodiment includes a linkage system 105 and a
spring/shock system 140 that supports the operator platform 70 and
suspends it from the chassis 10 as a unit. The linkage system may
comprise any system of links or connectors that permit the operator
platform 70 to move up and down as a unit, either vertically or in
a swinging motion, while still inhibiting or preventing rolling or
pitching, yawing, and linear side to side motion. For example, a
system of bell cranks or similar links could be employed. In the
present embodiment, the linkage system 105 takes the form of a
parallelogram linkage system. Parallelogram linkage system 105
includes front and back linkages 110, 120 that connect the front
and back portions of the operator platform 70 to the chassis 10 and
establish a travel path along which the operator platform 70 can
move while the suspension system 100 flexes during use.
[0043] Referring now to FIG. 2, front linkage 110 extends angularly
between the chassis 10 and the shelf 78 of foot support tier 76,
extending upwardly and rearwardly toward the back of the mower 5.
It includes an upper cross-bar 112 and a lower cross bar 114 that
extend transversely across the chassis 10. A pair of posts 115A,
115B extends between and connects the upper and lower cross-bars
112, 114 to each other. Ends of the upper cross-bar 112 are
pivotally connected to brackets 79 that extend from opposing sides
of the shelf 78. Ends of the lower cross-bar 114 are pivotally
connected to the opposing sides of the frame 12. This allows the
front linkage 110 to pivot about the attachment points between the
upper cross-bar 112 and the operator platform 70 and between the
lower cross-bar 114 and the frame 12.
[0044] Comparing the raised and lowered operator platforms 70 shown
in FIGS. 5 and 6, it can be seen that the lower and upper pairs of
attachment points between the front linkage 110 and chassis and
operator platform 70, respectively, define horizontal pivot axes
that are parallel to each other and extend transversely with
respect to the mower 5. This configuration transversely captures
the front of the operator platform 70 while allowing primarily
vertical translation of the platform 70 with respect to the chassis
10, along with limited longitudinal translation of the platform 70
with respect to the chassis 10, while substantially eliminating or
preventing (i) transverse swaying of the operator platform 70 with
respect to the chassis 10, (ii) rolling or pitching of the operator
platform 70 about its longitudinal axis, and (iii) yawing of the
operator platform 70 about an upright axis extending through a
middle portion of the chassis 10.
[0045] Referring now to FIGS. 2-4, back linkage 120 is mounted
higher upon the chassis 10 than the front linkage 110, extending
angularly between the chassis 10 and seat support tier 72 and
generally parallel to the front linkage 110 and thus also toward
the back of mower 5. As compared to the front linkage 110, back
linkage 120 has a relatively Y-shaped configuration (FIG. 2) with a
split upper cross-bar or upper cross-bars 122A, 122B, and a
relatively narrower lower cross-bar 124 when compared to the lower
cross bar 112 of the front linkage 110. Posts 125A, 125B are
connected to the upper cross-bars 122A, 122B and extend angularly
toward each other, at upper segments thereof, while lower segments
of the posts 125A, 125B extend from the upper segments, parallel to
each other, and are connected to opposing ends of the lower cross
bar 124. Each of upper cross-bars 122A, 122B of back linkage 120 is
pivotally connected to brackets or flanges that extend from
opposing sides of the seat support tier 72 of the operator platform
70. Ends of the lower cross-bar 124 of the back linkage 120 are
pivotally connected to a frame middle rail 13 that extends
longitudinally along the center line of the mower 5. Such pivoting
connections allow the back linkage 120 to pivot about the
attachment points between the upper cross bars 122A, 122B and the
seat support tier 72 and between the ends of the lower cross-bar
124 and the frame middle rail 13.
[0046] Referring now to FIGS. 2-6, similar to the pivot axes of the
front linkage 110, the lower and upper attachment points between
the back linkage 120 and frame middle rail 13 and operator platform
70 define a pair of horizontal pivot axes, with each axis being
parallel to the other and extending transversely across the mower
5. Furthermore, the back linkage 120 also transversely captures the
operator platform 70 while permitting vertical and some
longitudinal translation of the operator platform 70 with respect
to the chassis 10. Correspondingly, the front and back linkages
110, 120 of the parallelogram linkage system 105 cooperate with
each other to require the operator platform 70 to move as a unit,
substantially in a vertical direction while being biased upwardly
to a default position by the spring/shock system 140. A partially
loaded position of the operator platform 70 is seen in FIG. 3,
which the operator platform 70 may assume when an operator is
seated in the seat assembly 60 and the mower is standing still or
traveling but not traversing rough terrain. A lowered or fully
loaded position of the operator platform 70, in which the platform
70 contacts bumpstops 17 of the chassis 10, the parallel linkage
system 105 is folded down, and the suspension system 100 is fully
compressed, is seen in FIG. 5. A raised position of the operator
platform 70, in which the suspension system 100 is fully extended
without any weight on the platform, is seen in FIG. 6.
[0047] Referring now to FIGS. 2-4 and 9, spring/shock system 140 of
this embodiment has a mono-shock configuration and is provided
toward the back of the suspension system 100. Spring/shock system
140 includes a single coil-over type shock absorber having a damper
145 and a coil spring 148 that is concentrically housed around the
damper 145. The damper 145 includes a lower end 146 and an upper
end 147 that are axially movable relative to one another. The lower
end 146 extends through an opening in the frame middle rail 13 and
is pivotally connected to a yoke 16 (FIGS. 3 and 4) that is
connected to and extends below the frame middle rail 13 (FIGS. 3
and 4). The upper end 147 of the damper 145 extends through an
opening in the seat support tier 72 of the operator platform 70 and
is held between a pair of plates 272, 274 that are on opposing
sides of the opening and extend orthogonally downwardly from the
seat support tier 72. The upper end 147 is retained in arcuate
slots 273, 275 (FIG. 2) in the plates 272, 274 by a horizontal
cross pin 205 (FIGS. 9 and 10). The plates 272, 274 are positioned
forward of the lower end 146 of the damper 145, so that the upper
end 147 tilts forward, toward the front of the mower (FIG. 3), to a
variable extent which is explained in greater detail elsewhere
herein.
[0048] The force with which the spring 148 biases the operator
platform 70, corresponding to a suspension flexing stiffness, can
be modified by the operator by way of a course-stiffness adjuster
150 and a fine-stiffness adjuster 200.
[0049] Referring now to FIGS. 9, 10, and 11, course-stiffness
adjuster 150 allows for changing a preload setting of the spring
148 so as to accommodate for body weight differences of different
classes of users by providing a broad range of flexing stiffness
settings or relatively large scale adjustment increments of flexing
stiffness settings of the suspension system 100. An upper end of
spring 148 is fixed or captured with respect to an upper end of the
damper 145 by resting against a fixed cup or seat 149 (FIG. 9). The
course-stiffness adjuster 150 includes a cup or plate 155 that
supports a lower end of the spring 148 and that is moveable along a
longitudinal axis of the spring 148 and damper 145 so as to
establish a position of the lower end of the spring 148, thus
establishing a preload on the spring and, accordingly, establishing
a stiffness of the suspension system 100.
[0050] Still referring to FIGS. 10 and 11, the preload of the
spring 148 can be adjusted by adjusting the axial location of the
plate 155 relative to the upper seat 149 and then retaining the
plate 155 in a particular location, axially along the damper 145.
In the present embodiment, this adjustment is performed using a
course adjuster in the form of a collar-like cam 156 that extends
concentrically at least partially around the damper 145, below the
bottom of the spring 148. An upper annular wall 157 of cam 156
abuts a lower surface that is formed integrally with or otherwise
supports the plate 155. A ramped lower wall 158 of the cam 156 has
recesses 159 that are axially and circumferentially spaced from
each other. At any given time, one of the recesses 159 engages a
fixed projection 160 extending radially outwardly from the tubular
surface of the damper 145. Rotating the cam 156 to any of three
positions causes one of the three recesses 159 to rest on the
projection 160, hence setting the position of the upper annular
wall 157 and plate 155 along the length of the damper 145 and thus
the extent to which the spring 148 is preloaded. More preloading of
spring 148 provide a stiffer flexing of the suspension system 100
and less preloading of the spring 148 provides a softer flexing of
the suspension system 100. The cam 156 can be rotated by engaging
circumferentially spaced slots 161 in the bottom of the cam with a
spanner wrench (not shown) and then rotating the spanner
wrench.
[0051] Referring now to FIGS. 2 and 8-11, fine-stiffness adjuster
200 allows for adjusting suspension flexing stiffness within a
narrower range of setting when compared to, and being fully
encompassed within, the range of stiffness settings provided by the
course-stiffness adjuster 150. The fine-stiffness adjuster 200 is
configured to adjust the suspension stiffness so as to accommodate
for, for example, terrain differences encountered by each user
while operating the ride-on mower or intended operating speeds of
the mower 5 so that a stiffer setting can be used for faster
operating speeds and a softer setting can be used for slower
operating speeds. It also permits the stiffness to be tailored to
the prevailing desires of a particularly user. Importantly, this
adjustment can be performed by a seated operator using a simple
knob 226 and adjustment lever 225.
[0052] Referring now to FIG. 9, fine-stiffness adjuster 200
includes the pin 205 which, as discussed above, extends
transversely through the upper end 147 of the damper 145 and which
is supported in arcuate slots 273, 275 in the plates 272, 274 (FIG.
2). The lever 225 is coupled to the pin 205 by a spring linkage
210. Spring linkage 210 has a pair of horizontal legs 212, 214
(FIG. 9), each of which is pivotally connected to the pin 205 at
its rear end. A pair of bearings 211 is provided between the rear
ends of horizontal legs 212, 214 and the ends of pin 205 to
rollably support the plates 272, 274 of the operator platform 70 on
the spring/shock system 140. A front end of horizontal leg 214 is
pivotally connected to an upper end of an upright link 216. A lower
end of the upright link 216 is attached to a shaft 230 that is
supported at its ends and allowed to rotate by way of a pair of
bearings 231. Shaft 230 supports a v-link 218 at a vertex portion
of the v-link 218, from which upper and lower legs 220, 222 of the
v-link 218 extend angularly away from each other. V-link 218 is
axially movable with respect to the shaft 230 while being locked in
rotational unison with the shaft 230. An outer end of the upper leg
220 of the v-link 218 is pivotally connected to a front end of
horizontal leg 212. An outer end of lower leg 222 of the v-link 218
is bolted to an adjustment lever 225 with a pair of bolts 235,
237.
[0053] Still referring to FIG. 9, ends or caps of the bolts 235,
237 are spaced from the adjustment lever 225 which allows the
adjustment lever 225 to move with respect to the lower leg 222 of
v-link 218, in a direction that is parallel to the longitudinal
axis of shaft 230. In this way, the adjustment lever 225 is movable
axially along the bolts 235, 237, within the clearances between the
ends or caps of the bolts 235, 237 and the lower leg 222 of v-link
218. A spring 232 is provided concentrically around a shaft of bolt
235, between a head 236 of bolt 235 and the adjustment lever, so
that the spring 232 biases the adjustment lever 225 away from a
head 236 of the bolt 235, toward the lower leg 222 of v-link 218.
In this way, in a default state, the spring 232 holds corresponding
surfaces of adjustment lever 225 and lower leg 222 of v-link 218 in
a face-to-face abutment.
[0054] Referring now to FIGS. 8 and 9, in a default state, the
adjustment lever 225 sits in one of multiple slots 228 that are
defined between adjacent tabs 229 which extend from the wall 74,
into a generally vertical opening 227 in the wall 74 of the
operator platform 70. The previously mentioned knob 226 is attached
to an end of the adjustment lever 225 and provides a structure for
the operator to grasp while manipulating the adjustment lever 225.
Accordingly, the operator uses knob 226 to pull adjustment lever
225 out of a slot 228 and into the opening for repositioning the
adjustment lever 225 into a different one of the slots 228. After
aligning the adjustment lever 225 with a selected slot 228, the
operator releases the knob 226, whereby spring 232 pushes the
adjustment lever 225 away from the center line of the opening 227
and into one of respective slot 228.
[0055] Referring again to FIG. 9, shaft 230 defines a pivot axis of
the upright link 216 and v-link 218, so that when an operator
manipulates the knob 226, vertical movement of the adjustment lever
225 and lower leg 222 of v-link 218 drives the horizontal legs 212,
214 of the spring linkage 210 fore and aft to move the pin 205
along the arcuate slots 273, 275 in the plates 272, 274 by rolling
the bearings 211 along the edge-like surfaces of the plates 272,
274 that are defined at the perimeters of and face into the arcuate
slots 272, 275.
[0056] Referring now to FIGS. 8-11, the position of the adjustment
lever 225 along the length of the opening 227 determines the angle
of the spring/shock system 140 with respect to the operator
platform 70 and, more importantly, the position of the spring/shock
system 140 with respect to the front and back linkages 110, 120.
However, since the front and back linkages 110, 120 are parallel to
each other and pivot about their respective axis in unison to allow
unitized movement of the operator platform 70, effects of changing
position of the angle of the spring/shock system 140 with respect
to the back linkage 120 alone are discussed here while appreciating
that the same concepts are applicable at least by analogy to the
front linkage 110. Referring still to FIGS. 8-11, adjusting
stiffness of the suspension system 100 depends on the angle of the
spring/shock system 140 with respect to the back linkage 120
because the stiffness is, generally speaking, proportional to the
magnitude of the angle defined between the spring 148 of the
spring/shock system 140 and the back linkage. The closer the back
linkage 120 and spring/shock system 140 are to being perpendicular
to each other, the stiffer flexing of the suspension (FIG. 10). The
closer the back linkage 120 and spring/shock system 140 are to
being parallel to each other, the softer flexing of the suspension
(FIG. 11).
[0057] Referring now to FIG. 10, lowering the adjustment lever 225
toward the bottom of the opening 227 moves the pin 205 forward
along and the bearings 211 (FIG. 8) through the slots 273, 275
which tilts the upper end 147 of the damper 145 and the spring 148
forward and down, closer to being perpendicular to the back linkage
120. In this position, the biasing force supplied by the spring 148
is closer to directly opposing the direction of movement of the
back linkage 120. In the stiffer flexing of the suspension seen in
FIG. 10, for a given distance of movement of the operator platform
70, the spring 148 is compressed a distance that closely
approximates or corresponds to a distance that the back linkage 120
travels.
[0058] Referring now to FIG. 11, conversely, raising the adjustment
lever 225 toward the top of the opening 227 moves the pin 205
rearward along an the bearings 211 (FIG. 8) through the slots 273,
275 and tilts the upper end 147 of the spring/shock system 140
rearward and up, closer to being parallel to the back linkage 120.
In this position, the biasing force supplied by the spring 148 is
further from directly opposing the direction of movement of the
back linkage 120, when compared to the position the spring/shock
system 140 of FIG. 10. In the softer flexing of the suspension seen
in FIG. 11, for a given distance of movement of the operator
platform 70 and back linkage 120, the spring 148 is compressed a
lesser distance than when compared to the position the spring/shock
system 140 of FIG. 10 and contributing to such softer feel.
[0059] Referring again to FIGS. 8-11, these adjustments can be
performed simply and easily by a seated operator simply grasping
the knob 226, moving the adjustment lever 225 out of one of the
slots 228, raising or lowering the adjustment lever 225 within the
opening 227 into alignment with another desired slot 228, and
releasing the knob so as to let the spring 232 force the adjustment
lever 225 into the desired slot 228.
[0060] As indicated above, many changes and modifications may be
made to the present invention without departing from the spirit
thereof. The scope of some of these changes is discussed above. The
scope of others is apparent from the appended claims.
* * * * *